Definition of BOTTFLAG

The sampling event occurred without any incident being reported to BODC.

1

The filter in an in-situ sampling pump physically ruptured during sample resulting in an unquantifiable loss of sampled material.

2

Analytical evidence (e.g. surface water salinity measured on a sample collected at depth) indicates that the water sample has been contaminated by water from depths other than the depths of sampling.

3

The feedback indicator on the deck unit reported that the bottle closure command had failed. General Oceanics deck units used on NERC vessels in the 80s and 90s were renowned for reporting misfires when the bottle had been closed. This flag is also suitable for when a trigger command is mistakenly sent to a bottle that has previously been fired.

4

During the sampling deployment the bottle was fired in an order other than incrementing rosette position. Indicative of the potential for errors in the assignment of bottle firing depth, especially with General Oceanics rosettes.

5

Water was reported to be escaping from the bottle as the rosette was being recovered.

6

The bottle seals were observed to be incorrectly seated and the bottle was only part full of water on recovery.

7

Either the bottle was found to contain no sample on recovery or there was no bottle fitted to the rosette position fired (but SBE35 record may exist).

8

There is reason to doubt the accuracy of the sampling depth associated with the sample.

9

The bottle air vent had not been closed prior to deployment giving rise to a risk of sample contamination through leakage.

Definition of Rank

Rank 1 is a one-dimensional parameter

Rank 2 is a two-dimensional parameter

Rank 0 is a one-dimensional parameter describing the second dimension of a two-dimensional parameter (e.g. bin depths for moored ADCP data)

Open Data supplied by Natural Environment Research Council (NERC)

Technicon AutoAnalyzer II (AAII)

The AAII is a segmented flow analyzer used for automated colorimetric analysis. The apparatus uses 2 mm diameter glass tubing and pumps reagents at flow rates of 2 to 3 ml s-1, producing results at a typical rate of 30 to 60 samples per hour. The system comprises an autosampler, peristaltic pump, chemistry manifold a detector and a data acquisition software.

This instrument was replaced by the AA3 in 1997 which was upgraded to the AA3 HR systems in 2006.

Specifications

Frequency

420 kHz

Beam width

1.8° at -3 dB

Pulse lenght

0.1 m

Acoustic range precision

± 2.5 cm

Sampling rate

1 Hz

Tilt accuracy

± 0.5°

Tilt resolution

± 0.01°

Diameter of ensonified area(dependent on acoustic range)

0.9 m for 30 m range

3.1 m for 100 m range

6.3 m for 200 m range

Niskin Bottle

The Niskin bottle is a device used by oceanographers to collect subsurface seawater samples. It is a plastic bottle with caps and rubber seals at each end and is deployed with the caps held open, allowing free-flushing of the bottle as it moves through the water column.

Standard Niskin

The standard version of the bottle includes a plastic-coated metal spring or elastic cord running through the interior of the bottle that joins the two caps, and the caps are held open against the spring by plastic lanyards. When the bottle reaches the desired depth the lanyards are released by a pressure-actuated switch, command signal or messenger weight and the caps are forced shut and sealed, trapping the seawater sample.

Lever Action Niskin

The Lever Action Niskin Bottle differs from the standard version, in that the caps are held open during deployment by externally mounted stainless steel springs rather than an internal spring or cord. Lever Action Niskins are recommended for applications where a completely clear sample chamber is critical or for use in deep cold water.

Clean Sampling

A modified version of the standard Niskin bottle has been developed for clean sampling. This is teflon-coated and uses a latex cord to close the caps rather than a metal spring. The clean version of the Levered Action Niskin bottle is also teflon-coated and uses epoxy covered springs in place of the stainless steel springs. These bottles are specifically designed to minimise metal contamination when sampling trace metals.

Deployment

Bottles may be deployed singly clamped to a wire or in groups of up to 48 on a rosette. Standard bottles have a capacity between 1.7 and 30 L, while Lever Action bottles have a capacity between 1.7 and 12 L. Reversing thermometers may be attached to a spring-loaded disk that rotates through 180° on bottle closure.

AMT5 Nutrient (micromolar) measurements from CTD bottle samples

Originator's Protocol for Data Acquisition and Analysis

This data originates from analyses of bottle samples taken from 27 CTD casts.

The nutrient analyser used during the AMT-5 cruise was a five-channel Technicon AAII, segmented flow autoanalyser. The chemical methodologies used were: nitrate (Brewer and Riley, 1965), nitrite (Grasshoff, 1976), phosphate (Kirkwood, 1989) and silicate (Kirkwood, 1989). Water samples were taken from the 30 litre CTD/Rosette system (SeaBird) and sub-sampled into clean Nalgene bottles. The analysis of the samples was completed within 3 hours of sampling. Clean handling techniques were employed to avoid any contamination of the samples. No samples were stored.

All CTD samples were analysed successfully with a negligible sample loss rate. As usual, the Technicon system showed its reliability and reproducibility in the extreme environment of marine research.

Instrumentation Description

Not relevant to this data set.

BODC Data Processing Procedures

Data were submitted to BODC in Microsoft Excel spreadsheet format and saved to the BODC archive with reference PML020061. Sample metadata were checked against information held in the database. Originator's sample ID was matched based on CTD cast, bottle number and firing depth. OIDs were present in the database for the CTD events in the format AMT5xxx, where xxx was the cast number for the cruise.

For three casts (AMT5011, AMT5015 and AMT5030) samples were provided with sample depths that did not correspond to the depths samples for those casts. In these cases the samples were matched to the cruise report depths based on the provided bottle numbers provided in the file. These differences are listed below:

CTD cast

Bottle number

Originator's Depth (m)

Crusie Report Depth (m)

AMT5011

1

250

245

AMT5011

2

180

162

AMT5011

3

150

120

AMT5011

4

120

61

AMT5011

5

100

42

AMT5011

7

90

30

AMT5011

9

75

27

AMT5011

10

40

22

AMT5011

11

20

12

AMT5011

12

10

4

AMT5015

1

250

248

AMT5015

3

140

135

AMT5015

4

100

91

AMT5015

5

80

72

AMT5015

6

70

62

AMT5015

8

60

61

AMT5015

9

50

48

AMT5015

10

40

39

AMT5015

11

20

19

AMT5015

12

2

1

AMT5030

1

250

251

AMT5030

2

160

182

AMT5030

3

125

152

AMT5030

4

90

121

AMT5030

5

75

101

AMT5030

6

65

81

AMT5030

7

50

61

AMT5030

8

35

41

AMT5030

10

25

21

AMT5030

11

10

11

AMT5030

12

2

3

Although the cruise report indicates ammonia measurements were made on the CTD bottle samples and full set of nutrient analyses were made on underway samples along with nanomolar measurements, only the nitrate+nitrite, nitrite, phosphate and silicate measurements were supplied to BODC. The files also contained related data from incubations carried out during the cruise.

Data Quality Report

Problem Report

The Atlantic Meridional Transect (AMT) - Phase 1 (1995-2000)

Who was involved in the project?

The Atlantic Meridional Transect (AMT) programme was designed by and implemented as a collaboration between Plymouth Marine Laboratory (PML) and Southampton Oceanography Centre (SOC). The programme was hosted by Plymouth Marine Laboratory and involved additional researchers from UK and international universities throughout its duration.

What was the project about?

When AMT began in 1995 the programme provided a platform for international scientific collaboration, including the calibration and validation of SeaWiFs measurements and products. The programme provided an exceptional opportunity for nationally and internationally driven collaborative research and provided a platform for excellent multi-disciplinary oceanographic research. As an in situ observation system, the data collected by the AMT consortium informed on changes in biodiversity and function of the Atlantic ecosystem during this period of rapid change to our climate and biosphere.

The scientific aims were to assess:

mesoscale to basin scale phytoplankton processes

the functional interpretation of bio-optical signatures

the seasonal, regional and latitudinal variations in mesozooplankton dynamics

When was the project active?

The first phase of the AMT programme ran from 1995 to 2000 and consisted of a total of 12 cruises. A second phase of funding allowed the project to continue for the period 2002 to 2006 with a further 6 cruises.

Brief summary of the project fieldwork/data

The AMT programme undertook biological, chemical and physical oceanographic research during the annual return passage of the RRS James Clark Ross between the UK and the Falkland Islands or the RRS Discovery between the UK and Cape Town, a distance of up to 13,500 km. This transect crossed a range of ecosystems from sub-polar to tropical and from euphotic shelf seas and upwelling systems to oligotrophic mid-ocean gyres. The transect route was covered north-south in September/October and south-north in April/May of each year.

The measurements of hydrographic and bio-optical properties, plankton community structure and primary production completed on the first 12 transects (1995-2000) represent the most coherent set of repeated biogeochemical observations over ocean basin scales. This unique dataset has led to several important discoveries concerning the identification of oceanic provinces, validation of ocean colour algorithms, distributions of picoplankton, identifying new regional sinks of pCO2 and variability in rates of primary production and respiration.

Who funded the project?

The programme was funded by the Natural Environment Research Council (NERC) and further support was received from the National Aeronautics and Space Administration (NASA) with equipment and funding from the Sea-viewing Wild Field-of-view Sensor (SeaWiFS) project.

Please note: the supplied parameters may not have been sampled from all the bottle firings described in the table above. Cross-match the Sample Reference Number above against the SAMPRFNM value in the data file to identify the relevant metadata.